I. Field of the Invention
The present invention relates generally to high vacuum housings and, more particularly, to such a housing having novel means for sealing an interior chamber of the housing.
II. Description of the Prior Art
High vacuum housings, such as housings for x-ray sources of the type used both for medical applications as well as for material inspection devices, typically comprise two parts which are detachably secured together and form an interior chamber.
Maintaining a high vacuum within the housing chamber has presented unique challenges. For example, common elastomeric seals are inappropriate for such housings since outgassing from such seals would adversely affect the vacuum contained within the housing chamber.
Consequently, in order to sealingly secure the housing parts together, it has been the previously known practice to position an annular ring constructed of a malleable material, such as copper, in between the housing parts. The annular seal ring, furthermore, is relatively thick, e.g. 1/16 of an inch in thickness.
In order to complete the seal between the housing parts and the annular ring, the previously known high vacuum housings typically include sawtooth shaped annular projections and recesses. Thus, when the housing parts are clamnpingly secured together, typically by bolting the housing parts together, the sawtooth rings on the housing parts extrude the sealing ring between the projections and recesses thus sealing the housing parts together.
A major disadvantage of these previously known housings is that, in order to ensure that the sealing ring is evenly and sealingly extruded between the housing parts, the housing parts are necessarily massive in construction to prevent warpage or distortion of the housing parts as the ring is extruded. Furthermore, in order to apply the compressive force between the housing parts necessary to properly extrude the sealing ring between the housing parts, it has been previously necessary to provide a plurality of circumferentially spaced, large bolts between the housing parts. These bolts are sequentially tightened thus drawing the housing parts together and extruding the seal ring. Consequently, the assembly of the housing is not only tedious and time consuming, but also results in increased material costs due to the massive construction required for the housing parts.